JJG 188-2017 PDF English
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Sound Level Meters
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| JJG 188-2005 | English | RFQ |
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Verification regulation of sound level meters
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| JJG 188-1990 | English | 599 |
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(Sound Level Meter test procedures)
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JJG 188-2017: Sound Level Meters---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/JJG188-2017
JJG
METERING & VERIFICATION REGULATION
Sound level meters
Issued on. NOVEMBER 20, 2017
Implemented on. MAY 20, 2018
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the People‘s Republic of China.
Verification regulation of sound level meters
Under the jurisdiction of. National Acoustic Metrology Technical Committee
Drafting organizations.
China National Institute of Metrology
Hubei Institute of Metrology and Testing Technology
Hangzhou Aihua Instrument Co., Ltd.
China Shipbuilding Industry Corporation 701st Institute
Jilin Institute of Metrology
This regulation is entrusted to the National Acoustic Metrology Technical Committee
for interpretation.
JJG 118-2017
Replacing verification
part of JJG 188-2002
Drafters of this Regulation.
Xu Huan (China National Institute of Metrology)
Bai Ying (China National Institute of Metrology)
Niu Feng (China National Institute of Metrology)
Yao Qiuping (Hubei Institute of Metrology and Testing Technology)
Zhang Shaodong (Hangzhou Aihua Instrument Co., Ltd.)
Zhu Chuanhuan (China Shipbuilding Industry Corporation 701st Institute)
Fang Facheng (Jilin Institute of Metrology)
Table of Contents
Introduction... 5
1 Scope... 7
2 References... 7
3 Terms and measurement units... 8
4 Overview... 16
5 Metrological performance requirements... 16
5.1 Indication sound level adjustment... 16
5.2 Frequency weighting... 17
5.3 Frequency weighting at 1kHz... 19
5.4 Level linearity... 19
5.5 Self-generated noise... 20
5.6 Time weightings F and S... 20
5.7 Toneburst response... 21
5.8 Repeated toneburst response... 22
5.9 Overload indication... 23
5.10 C-weighted peak sound level... 23
6 General technical requirements... 24
6.1 Marking... 24
6.2 Functional inspection... 24
7 Measuring instrument control... 24
7.1 Verification conditions... 25
7.2 Verification items... 26
7.3 Verification method... 27
7.4 Processing of verification results... 38
7.5 Verification cycle... 38
Appendix A Maximum allowable measurement uncertainty... 39
Appendix B Other methods for frequency weighted acoustic signal testing... 40
Appendix C Inner page format of the verification certificate and verification result
notice... 43
1 Scope
This Regulation applies to the initial verification, subsequent verification, in-use
inspection of time-weighted sound level meters, integral average sound level meters,
integrating sound level meters that meet the requirements of IEC 61672-1.
2 References
This Regulation makes reference to the following documents.
JJG 176-2005 Verification regulation of sound calibrators
JJG 482-2005 Verification regulation of laboratory standard microphones (free-field
reciprocity method)
JJG 790-2005 Verification regulation of laboratory standard microphones (coupler
reciprocity method)
JJG 1019-2007 Verification regulation of working standard microphones (coupler
comparison method)
JJF 1001-2011 General terms in metrology and their definitions
JJF 1034-2005 Metrological terms and their definitions for acoustics
JJF 1147-2006 Verification specification for acoustic performance of anechoic
rooms and hemi-anechoic rooms
JJF 1293-2011 Verification specification for electrostatic actuators
3 Terms and measurement units
This Regulation adopts the quantities and units specified in GB/T 3102.7.
The following terms and definitions defined in JJF 1001-2011, JJF 1034-2005, GB/T
3947-1996, as well as the following terms and definitions, apply to this Regulation.
3.1 Sound pressure
The difference between the instantaneous total pressure and the corresponding static
pressure.
3.2 Sound pressure level
The logarithm to the base 10 of the ratio -- of the time mean square of the sound
pressure signal to the square of the reference value -- multiplied by 10.
3.3 Frequency weighting
The difference -- between the frequency-weighted signal level indicated on the
display device and the corresponding constant amplitude sinusoidal input signal
level, which is a specific function of frequency.
3.4 Time weighting
A time exponential function with a specified time constant, that weights the square
of the sound pressure signal.
3.10 Time-average sound level
Equivalent continuous sound level
4 Overview
The sound level meter usually consists of a microphone, a preamplifier, a signal
processor, and a display. The signal processor includes a specified amplifier with
controllable frequency response, a device for squaring the time-varying sound pressure
with frequency weighting, a time integrator or time averager.
5 Metrological performance requirements
5.1 Indication sound level adjustment
It shall be performed at the reference sound pressure level in the reference level range
and at the verification check frequency in the range of 160 Hz ~ 1250 Hz.
5.2 Frequency weighting
5.2.1 The sound level meter shall have frequency weighting A; the Class 1 sound level
meter shall also have frequency weighting C. The sound level meter that measures the
C-weighted peak sound level shall also be able to measure the C-weighted time average
sound level.
5.2.4 For sound level meters and configurations with nominal operating modes
specified in the instruction manual, the relative frequency-weighted free-field response
and relative frequency-weighted random-incidence response (if applicable) shall
comply with the corresponding frequency weightings and acceptance limits in Table 1.
5.3 Frequency weighting at 1kHz
At the reference sound pressure level within the reference level range, for a 1 kHz
steady-state sinusoidal electrical signal, the difference -- between the indicated sound
level measured on C weighting and Z weighting and the indicated sound level measured
on A weighting -- shall not exceed ±0.2 dB. This requirement does not apply to the
indication of peak sound level.
5.4 Level linearity
5.4.1 Within the reference level range, the level linearity range at 1 kHz frequency shall
be at least 60 dB.
5.6 Time weightings F and S
5.6.1 The design target for the exponential time constant of the sound level meter time
weighting F is 0.125 s and the time weighting S is 1 s. The decay rate of the indicated
sound level shall be measured by suddenly terminating the input 4 kHz steady-state
sinusoidal electrical signal. The decay rate of the time weighting F shall be between
31.0 dB/s and 38.5 dB/s; the time weighting S shall be between 3.6 dB/s and 5.1 dB/s.
5.7 Toneburst response
5.8 Repeated toneburst response
5.8.1 The requirements for repeated toneburst response apply to A-weighting as well as
C and Z-weighting. The deviation of the measured time-averaged sound level from the
time-averaged sound level calculated for the corresponding toneburst sequence, using
a 4 kHz repeated electric toneburst sequence of the same amplitude and duration, shall
be within the acceptance limit specified for the sound exposure level toneburst response
in Table 2.The measurement shall be made on the reference level range of the sound
level meter, 3 dB below the upper limit of the corresponding 4 kHz level linearity range,
with the duration of the toneburst of 0.25 ms ~ 1 s.
7 Measuring instrument control
Measuring instrument control includes initial verification, subsequent verification, in-
use inspection.
7.1 Verification conditions
7.1.1 Environmental conditions
The verification environmental conditions of the sound level meter are as follows.
7.1.2 Reference environmental conditions
The reference environmental conditions of the sound level meter are as follows.
allowable measurement uncertainty in Appendix A.
7.1.3 Measurement standards and main supporting equipment
7.3 Verification method
7.3.1 Appearance inspection
Visual inspection or manual operation.
7.3.3 Frequency weighting
7.3.3.1 Overview
Among the frequency weightings provided by the sound level meter, at least one shall
be tested with an acoustic signal; the other frequency weightings may use either an
acoustic signal or an electrical signal. For the first verification of the sound level meter,
at least one frequency weighting shall be used to calibrate the acoustic signal and the
electrical signal.
JJG
METERING & VERIFICATION REGULATION
Sound level meters
Issued on. NOVEMBER 20, 2017
Implemented on. MAY 20, 2018
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the People‘s Republic of China.
Verification regulation of sound level meters
Under the jurisdiction of. National Acoustic Metrology Technical Committee
Drafting organizations.
China National Institute of Metrology
Hubei Institute of Metrology and Testing Technology
Hangzhou Aihua Instrument Co., Ltd.
China Shipbuilding Industry Corporation 701st Institute
Jilin Institute of Metrology
This regulation is entrusted to the National Acoustic Metrology Technical Committee
for interpretation.
JJG 118-2017
Replacing verification
part of JJG 188-2002
Drafters of this Regulation.
Xu Huan (China National Institute of Metrology)
Bai Ying (China National Institute of Metrology)
Niu Feng (China National Institute of Metrology)
Yao Qiuping (Hubei Institute of Metrology and Testing Technology)
Zhang Shaodong (Hangzhou Aihua Instrument Co., Ltd.)
Zhu Chuanhuan (China Shipbuilding Industry Corporation 701st Institute)
Fang Facheng (Jilin Institute of Metrology)
Table of Contents
Introduction... 5
1 Scope... 7
2 References... 7
3 Terms and measurement units... 8
4 Overview... 16
5 Metrological performance requirements... 16
5.1 Indication sound level adjustment... 16
5.2 Frequency weighting... 17
5.3 Frequency weighting at 1kHz... 19
5.4 Level linearity... 19
5.5 Self-generated noise... 20
5.6 Time weightings F and S... 20
5.7 Toneburst response... 21
5.8 Repeated toneburst response... 22
5.9 Overload indication... 23
5.10 C-weighted peak sound level... 23
6 General technical requirements... 24
6.1 Marking... 24
6.2 Functional inspection... 24
7 Measuring instrument control... 24
7.1 Verification conditions... 25
7.2 Verification items... 26
7.3 Verification method... 27
7.4 Processing of verification results... 38
7.5 Verification cycle... 38
Appendix A Maximum allowable measurement uncertainty... 39
Appendix B Other methods for frequency weighted acoustic signal testing... 40
Appendix C Inner page format of the verification certificate and verification result
notice... 43
1 Scope
This Regulation applies to the initial verification, subsequent verification, in-use
inspection of time-weighted sound level meters, integral average sound level meters,
integrating sound level meters that meet the requirements of IEC 61672-1.
2 References
This Regulation makes reference to the following documents.
JJG 176-2005 Verification regulation of sound calibrators
JJG 482-2005 Verification regulation of laboratory standard microphones (free-field
reciprocity method)
JJG 790-2005 Verification regulation of laboratory standard microphones (coupler
reciprocity method)
JJG 1019-2007 Verification regulation of working standard microphones (coupler
comparison method)
JJF 1001-2011 General terms in metrology and their definitions
JJF 1034-2005 Metrological terms and their definitions for acoustics
JJF 1147-2006 Verification specification for acoustic performance of anechoic
rooms and hemi-anechoic rooms
JJF 1293-2011 Verification specification for electrostatic actuators
3 Terms and measurement units
This Regulation adopts the quantities and units specified in GB/T 3102.7.
The following terms and definitions defined in JJF 1001-2011, JJF 1034-2005, GB/T
3947-1996, as well as the following terms and definitions, apply to this Regulation.
3.1 Sound pressure
The difference between the instantaneous total pressure and the corresponding static
pressure.
3.2 Sound pressure level
The logarithm to the base 10 of the ratio -- of the time mean square of the sound
pressure signal to the square of the reference value -- multiplied by 10.
3.3 Frequency weighting
The difference -- between the frequency-weighted signal level indicated on the
display device and the corresponding constant amplitude sinusoidal input signal
level, which is a specific function of frequency.
3.4 Time weighting
A time exponential function with a specified time constant, that weights the square
of the sound pressure signal.
3.10 Time-average sound level
Equivalent continuous sound level
4 Overview
The sound level meter usually consists of a microphone, a preamplifier, a signal
processor, and a display. The signal processor includes a specified amplifier with
controllable frequency response, a device for squaring the time-varying sound pressure
with frequency weighting, a time integrator or time averager.
5 Metrological performance requirements
5.1 Indication sound level adjustment
It shall be performed at the reference sound pressure level in the reference level range
and at the verification check frequency in the range of 160 Hz ~ 1250 Hz.
5.2 Frequency weighting
5.2.1 The sound level meter shall have frequency weighting A; the Class 1 sound level
meter shall also have frequency weighting C. The sound level meter that measures the
C-weighted peak sound level shall also be able to measure the C-weighted time average
sound level.
5.2.4 For sound level meters and configurations with nominal operating modes
specified in the instruction manual, the relative frequency-weighted free-field response
and relative frequency-weighted random-incidence response (if applicable) shall
comply with the corresponding frequency weightings and acceptance limits in Table 1.
5.3 Frequency weighting at 1kHz
At the reference sound pressure level within the reference level range, for a 1 kHz
steady-state sinusoidal electrical signal, the difference -- between the indicated sound
level measured on C weighting and Z weighting and the indicated sound level measured
on A weighting -- shall not exceed ±0.2 dB. This requirement does not apply to the
indication of peak sound level.
5.4 Level linearity
5.4.1 Within the reference level range, the level linearity range at 1 kHz frequency shall
be at least 60 dB.
5.6 Time weightings F and S
5.6.1 The design target for the exponential time constant of the sound level meter time
weighting F is 0.125 s and the time weighting S is 1 s. The decay rate of the indicated
sound level shall be measured by suddenly terminating the input 4 kHz steady-state
sinusoidal electrical signal. The decay rate of the time weighting F shall be between
31.0 dB/s and 38.5 dB/s; the time weighting S shall be between 3.6 dB/s and 5.1 dB/s.
5.7 Toneburst response
5.8 Repeated toneburst response
5.8.1 The requirements for repeated toneburst response apply to A-weighting as well as
C and Z-weighting. The deviation of the measured time-averaged sound level from the
time-averaged sound level calculated for the corresponding toneburst sequence, using
a 4 kHz repeated electric toneburst sequence of the same amplitude and duration, shall
be within the acceptance limit specified for the sound exposure level toneburst response
in Table 2.The measurement shall be made on the reference level range of the sound
level meter, 3 dB below the upper limit of the corresponding 4 kHz level linearity range,
with the duration of the toneburst of 0.25 ms ~ 1 s.
7 Measuring instrument control
Measuring instrument control includes initial verification, subsequent verification, in-
use inspection.
7.1 Verification conditions
7.1.1 Environmental conditions
The verification environmental conditions of the sound level meter are as follows.
7.1.2 Reference environmental conditions
The reference environmental conditions of the sound level meter are as follows.
allowable measurement uncertainty in Appendix A.
7.1.3 Measurement standards and main supporting equipment
7.3 Verification method
7.3.1 Appearance inspection
Visual inspection or manual operation.
7.3.3 Frequency weighting
7.3.3.1 Overview
Among the frequency weightings provided by the sound level meter, at least one shall
be tested with an acoustic signal; the other frequency weightings may use either an
acoustic signal or an electrical signal. For the first verification of the sound level meter,
at least one frequency weighting shall be used to calibrate the acoustic signal and the
electrical signal.
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
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